US8587376B2ActiveUtilityPatentIndex 83
Automatic gain control
Est. expiryJul 29, 2030(~4.1 yrs left)· nominal 20-yr term from priority
Inventors:REINING FRIEDRICH
H03G 7/06H03G 3/001H03G 3/3005
83
PatentIndex Score
9
Cited by
14
References
13
Claims
Abstract
An automatic gain controller is disclosed. The AGC includes an input for monitoring a signal associated with an amplifier and a gain control circuit for controlling the gain of the amplifier in response to the monitored signal, wherein the gain control circuit is adapted to control the gain of the amplifier in accordance with a gain control function having continuously variable attack and release time constants, both of which depend on the amplitude of the monitored signal.
Claims
exact text as granted — not AI-modifiedThe invention claimed is:
1. An automatic gain controller (AGC) comprising:
an input configured to monitor a signal associated with an amplifier; and
a gain control circuit configured to control a gain of the amplifier in response to the monitored signal in accordance with a gain control function having continuously variable attack and release time constants, both of which depend on an amplitude of the monitored signal,
wherein the monitored signal is an input signal to the amplifier and the gain control function is equal to:
1
A
(
n
-
1
)
λ
·
M
(
q
)
,
A(n−1) is a previous value of the gain of the amplifier, λ is a constant, and M(q) is a gain control factor that depends on the amplitude of the monitored signal and provides the continuously variable attack and release time constants.
2. The AGC according to claim 1 , wherein the monitored signal is an output signal from the amplifier, the gain control function is equal to A(n−1) λ *M(q), A(n−1) is a previous value of the gain of the amplifier, λ is a constant, and M(q) is a gain control factor that depends on the amplitude of the monitored signal and provides the continuously variable attack and release time constants.
3. The AGC according to claim 2 , wherein the gain control factor has a value of 1 in a mid-scale region in which the monitored signal has an amplitude between first and second predefined values and monotonically decreases toward a value of zero in lower and upper scale regions in which the monitored signal has an amplitude between a negative full scale and the first predefined value and between the second predefined value and a positive full scale respectively.
4. The AGC according to claim 3 , wherein the gain control factor is defined by M(q)=1−abs(q 15 ), where q is the magnitude of the monitored signal and is normalized to fall within a range of −1 to +1.
5. The AGC according to claim 2 , wherein the gain control factor has a value of 1 in a mid-scale region in which the monitored signal has an amplitude between first and second predefined values and a value lower than 1 in lower and upper scale regions in which the monitored signal has an amplitude between negative full scale and the first predefined value and between the second predefined value and positive full scale respectively.
6. The AGC according to claim 2 , further comprising:
a memory addressable using an address value based on the monitored signal to retrieve a corresponding value of the gain control factor.
7. A system comprising
a first AGC comprising
an input configured to monitor a signal associated with an amplifier, and
a gain control circuit configured to control a gain of the amplifier in response to the monitored signal in accordance with a gain control function having continuously variable attack and release time constants, both of which depend on the amplitude of the monitored signal, wherein the monitored signal is an output signal from the amplifier and the gain control function is equal to A(n−1) λ *M(q), where A(n−1) is a previous value of the gain of the amplifier, λ is a constant, and M(q) is a gain control factor that depends on the amplitude of the monitored signal and provides the continuously variable attack and release time constants for controlling the gain of a first amplifier, the input of the first AGC being coupled to the output of the first amplifier;
a second AGC configured to control a gain of a second amplifier, the input of the second AGC being coupled to the input of the second amplifier; and
a transmission channel configured to couple the output of the first amplifier to the input of the second amplifier, wherein the first and second amplifiers are substantially identical.
8. A method of automatic gain control for an amplifier, the method comprising:
monitoring a signal associated with an amplifier, and
controlling a gain of the amplifier in response to the monitored signal, in accordance with a gain control function having continuously variable attack and release time constants, both of which depend on an amplitude of the monitored signal,
wherein the monitored signal is an input signal to the amplifier, the gain control function is equal to:
1
A
(
n
-
1
)
λ
·
M
(
q
)
,
A(n−1) is a previous value of the gain of the amplifier, λ is a constant, and M(q) is a gain control factor that depends on the amplitude of the monitored signal and provides the continuously variable attack and release time constants.
9. The method of automatic gain control according to claim 8 , wherein the monitored signal is an output signal from the amplifier, the gain control function is equal to A(n−1) λ *M(q), A(n−1) is a previous value of the gain of the amplifier, λ is a constant, and M(q) is a gain control factor that depends on the amplitude of the monitored signal and provides the continuously variable attack and release time constants.
10. The method of automatic gain control according to claim 9 , wherein the gain control factor has a value of 1 in a mid-scale region in which the monitored signal has an amplitude between first and second predefined values and monotonically decreases towards a value of zero in lower and upper scale regions in which the monitored signal has an amplitude between negative full scale and the first predefined value and between the second predefined value and positive full scale respectively.
11. The method of automatic gain control according to claim 10 , wherein the gain control factor is defined by: M(q)=1−abs(q 15 ), where q is the magnitude of the monitored signal, normalized to fall within a range of −1 to +1.
12. The method of automatic gain control according to claim 9 , wherein the gain control factor has a value of 1 in a mid-scale region in which the monitored signal has an amplitude between first and second predefined values and a value lower than 1 in lower and upper scale regions in which the monitored signal has an amplitude between negative full scale and the first predefined value and between the second predefined value and positive full scale respectively.
13. A method of transmitting a signal over a transmission channel, the method comprising controlling a gain of a first amplifier using a method comprising:
monitoring a signal associated with the first amplifier, and
controlling the gain of the first amplifier in response to the monitored signal, in accordance with a gain control function having continuously variable attack and release time constants, both of which depend on the amplitude of the monitored signal, wherein the monitored signal is an output signal from the first amplifier, the gain control function is equal to A(n−1) λ *M(q), A(n−1) is a previous value of the gain of the amplifier, λ is a constant, and M(q) is a gain control factor that depends on the amplitude of the monitored signal and provides the continuously variable attack and release time constants, the monitored signal being the output signal of the first amplifier;
transmitting the output signal from the first amplifier over the transmission channel;
receiving the transmitted signal from the transmission channel at the input of a second amplifier; and
controlling the gain of the second amplifier, the monitored signal being the input signal to the second amplifier.Cited by (0)
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